Conventionally, a driving support system is used to support a driver in a subject vehicle by providing information on, for example, surrounding traffic or the like while the subject vehicle is traveling. The information on the surrounding traffic is provided for the driver of the subject vehicle in a timely manner, and that allows the driver to suitably operate an acceleration pedal, a brake pedal or the like based on, for example, recognition of closeness to other vehicles. Further, the driving support system disclosed in U.S. Pat. No. 5,865,265 and Japanese Patent Application JP-A-2000-311298 provides the information for the driver in a variable manner in terms of information provision timing, basically according to a condition of surrounding traffic. The information provision timing may also be varied according preference of the driver. In this manner, the driver utilizes the provided information for improvement of safety and appropriateness of driving.
In recent years, driving operations of the vehicle are partially automated by combining sensing devices with the driving mechanism. For example, a radar for watching/scanning a front space of the vehicle combined with acceleration mechanism for controlling vehicle speed is getting widely used as a radar cruise system or an adaptive cruise control system. Further, a parking assist system for automatically controlling a steering wheel as well as vehicle speed to suitably maneuver the vehicle into a target parking lot is now commercially available.
Even in an occasion of using those automation technologies, provision of information on the surrounding traffic for the driver is beneficial from various viewpoints. That is, the vehicle may be involved in a hazardous/dangerous situation for various reasons even when the vehicle is automatically controlled. (In this application, a full-automated driving and a partially-automated driving are both designated as an automated driving.)
However, the provision of the information should appropriately be controlled according to the degree of automation of the driving. In other words, an appropriate manner of information provision should be differently arranged for a fully-automated driving, a partially-automated driving and a manual driving in terms of suitability for supporting the driving operation in each of the driving modes of the vehicle.